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大约20%年龄较大的女性，在接受乳房保留手术后，有延迟或是未完成放射线治疗的情形，这将影响免于疾病预后。这项研究发表在12月1日的癌症期刊，结果显示非白人女性与未能即时接受放线治疗有关。
研究中共有7,791位第一期原位性管腺瘤（DICS）且年龄65岁以上的女性，其中1,297位有延迟接受放射线治疗的情形，而269位未完成放射线治疗。第一期且延迟放射线治疗病患，接下来比较可能发生乳房相关的事件（胜算比[OR]为1.14），第一期且未完成放射线治疗女性的整体死亡率也比较高（OR为1.32）。
主要作者、纽约市威利康乃尔大学医学院公共卫生部门健康政策分部的副教授Heather Taffet Gold医师在一项声明中表示，对早期乳癌患者而言，手术后放射线治疗的时间点，对于降低后续再发、或是新的乳房恶性肿瘤是非常重要的。有延迟状况的一个可能因素是，照护的整合是一个挑战，就像治疗经常是由不同专业的照护者所提供，包括外科医师、放射科医师以及内科肿瘤医师。
一项探索性的研究结果显示，手术后延迟接受放射线治疗超过12周以上，或是在化学治疗后8周之后，这些病患不论疾病分期，接下来发生乳癌事件的比例高出4倍。对于所有病患而言，没有完成放射线治疗并不会增加疾病再发或是复发风险，但对于那些第一期疾病病患，未完成放射线治疗与整体存活较差有关（OR，1.32）。
即使乳房保留手术后放射线治疗已经证实可以降低局部再发风险，但统计结果显示许多病患接受并不完整的治疗。举例来说，作者们表示，仅有39%年龄在65岁以上且罹患DCIS的女性接受肿块切除后乳房放射线治疗，而80%早期侵入性乳癌在肿块切除术后接受放射线治疗。
【种族及贫穷程度与延迟治疗有关】
Gold博士与其同事使用the Surveillance, Epidemiology, and End Results（SEER）医疗保险资料库找出自1991年到1999年之间首次被诊断原发性DCIS或是第一期乳癌的女性；DCIS患者的平均后续追踪时间为6.3年（共1,062位），第一期乳癌女性为5.9年（共6,765位），范围自1~9年。
他们发现，不论是在哪一个疾病分期，有16%的女性手术后延迟接受放射线治疗超过8周，或是化学治疗后4之周。这个族群中，约3%的病患也没有完成完整疗程的放射线治疗。
卡方检定后发现，住在贫穷程度较高的女性比较容易有延迟放射线治疗的情形（对第一期乳癌女性而言P=.09）、或是没有完成疗程（对第一期乳癌女性而言P=.03）；此外，种族也与第一期患者有较高的延迟治疗率有关，黑人女性比白人女性更容易延迟治疗（OR，1.56）。居住在放射肿瘤科医师密度较高地区的黑人女性延迟治疗的机率则较低（OR，0.73）。
分析显示，预测后续乳癌发生率较低的因子，包括年龄较大、贫穷程度低、居住在放射肿瘤科医师密度较高地区以及已婚；因为一个地区的放射肿瘤科医师密度较高会改善免于疾病及整体存活率，研究者们表示这些因素可能是接受到医疗照护服务的指标。
作者表示，对DCIS与早期侵入性乳癌患者患者而言，延迟放射线治疗的效应并未在随机分派研究中评估。这项全国的代表性族群研究，针对罹患DCIS或是早期侵入性乳癌女性，收纳了在随机分派研究中经常未被收纳的病患， 且提供我们一个独特的机会，来研究延迟与未完成放射线治疗的效应。
他们的结论是，为了改善早期侵入性乳癌治疗的健康预后，临床医师需要在照护流程中介入，以降低时间延迟，且鼓励完成疗程。机构与照护者应该采取支持性服务，并且提供教材来鼓励并简化接受最佳放射线治疗，以期改善免于疾病与整体存活率。
这些研究由美国癌症医学会赞助。
Delay in Radiation Therapy Affects Outcomes in Breast Cancer
By Roxanne Nelson
Medscape Medical News
As many as 20% of older women experience delayed or incomplete radiation treatment after breast-conserving surgery, and this can adversely affect disease-free survival. The study, published in the December 1 issue of Cancer, also showed that nonwhite race negatively influenced timely receipt of radiation therapy.
In a sample of 7791 women with stage?I cancer or ductal carcinoma in situ (DCIS) 65 years and older, 1297 experienced delayed radiotherapy and 269 had incomplete radiotherapy. Stage?I breast cancer patients with delayed radiation therapy were more likely to experience a subsequent breast event (odds ratio [OR], 1.14). The rate of overall mortality was also higher among stage?I breast cancer patients with incomplete radiation therapy (OR, 1.32).
"Timeliness of post-surgical radiotherapy is important in reducing the risk of subsequent recurrence or new breast malignancies in patients with early breast cancer. Delaying treatment by 8 weeks or more significantly increased the odds for recurrence," said lead author Heather Taffet Gold, MD, assistant professor of public health in the Division of Health Policy in the Department of Public Health at Weill Cornell Medical College, in New York City, in a statement. "One possible reason for the delays is that the coordination of care can be a challenge, as treatment is usually delivered by multiple providers from different specialties, including surgeons, radiation oncologists, and medical oncologists,"
An exploratory analysis suggested that a delay in radiation therapy of 12 or more weeks after surgery, or 8 or more weeks after chemotherapy, were more than 4 times more likely to experience a subsequent breast cancer event, regardless of stage. For all patients, noncompletion of radiation therapy was not associated with an increased risk for recurrence or relapse, but among those with stage?I disease, incomplete radiotherapy was associated with worse overall survival (OR, 1.32).
Even though radiation therapy after breast-conserving surgery has been shown to reduce the risk for local recurrence, statistics suggest that many patients have received suboptimal treatment. As an example, the authors note that only 39% of women 65 years and older with DCIS receive postlumpectomy breast irradiation, whereas 80% of patients with early invasive breast cancer received radiotherapy after a lumpectomy.
Race and Poverty Level Associated With Delayed Treatment
Dr. Gold and colleagues used the Surveillance, Epidemiology, and End Results (SEER)-Medicare database to identify women who were diagnosed from 1991 to 1999 with a first primary DCIS or stage?I breast cancer. The median follow-up time was 6.3 years for DCIS (n?= 1026) and 5.9 years for stage?I disease (n?= 6765), and ranged from 1 to 9 years.
They found that 16% of the women had experienced a delay in the initiation of radiation therapy of more than 8 weeks after surgery, or more than 4 weeks after chemotherapy, and this included all stages. Approximately 3% of the patients in this cohort also did not complete the full course of radiation treatment.
Chi-square testing revealed that women residing in an area of high poverty were more likely to have a delay in radiation therapy (P?=.09 for stage?I only) and noncompletion (P?= .03 for stage?I). Race was also associated with a higher probability of delaying treatment among women with stage?I disease, and black women were more likely to delay treatment than white women (OR, 1.56). Patients residing in areas where there was a high density of radiation oncologists were less likely to delay therapy (OR, 0.73).
Analysis showed that factors predictive of a lower probability of a subsequent breast cancer event included older age, lower levels of poverty, higher density of radiation oncologists, and being married. Because density of radiation oncologists in an area improved both disease-free and overall survival, the researchers note that this factor might be an indicator of access to healthcare services.
The effect of delayed radiation therapy on disease-free survival in both DCIS and early invasive breast cancer patients has not been evaluated in randomized clinical trials, the authors say. "This nationally representative population-based study of older women with DCIS or early invasive breast cancer included women who are often underrepresented in randomized controlled trials, and gave us a unique opportunity to study delay and noncompletion of radiation therapy."
To improve health outcomes after treatment for early invasive breast cancer, clinicians need to intervene in the care process to reduce delay time and encourage completion, they conclude. "Facilities and providers should implement supportive services and provide educational materials to encourage and ease access to optimal [radiation therapy], thereby improving [disease-free] and overall survival."
The study was supported by the American Cancer Society.
Cancer. 2008;113:3108-3115.